The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Loss of traction between a road surface and a tire can occur during acceleration or deceleration. In both cases the available traction force between the tire and the road surface falls below a threshold capacity which is required to maintain the vehicle on a desired course and speed. Loss of traction force can also occur when a vehicle traveling at constant throttle encounters a sudden drop in friction coefficient of the road surface, which can cause wheel slip unless the engine controller proactively cuts the throttle. A delay of as little as a tenth of a second in determining the onset of traction loss without correction in a throttle setting can result in loss of vehicle control. Algorithms are therefore commonly used to calculate corrections for vehicle control. Due to the availability of speed sensors, most algorithms for throttle control rely mainly on speed information to determine wheel slip to take a follow-up action. Because of the highly non-linear relationship between the throttle input and the resultant wheel speed, convoluted algorithms are used to determine the throttle action for any given slip condition.
Attempts have been made to model systems and estimate several quantities such as torque and desired throttle position to reduce the complexity of the algorithms used, however algorithms generally cannot calculate exact torque values for all conditions. Known models therefore estimate torque and apply ground/wheel friction coefficients that are saved in tables of data. Because the tables of data are themselves empirical or estimations the data may not be responsive to rapidly changing conditions or determination of potential loss of traction at very early stages.